Clathrates of butylphtualide with cyclodextrin or its derivatives, a process for their preparation and the use thereof

ABSTRACT

The present invention relates to the inclusion complexes of butylphthalide, which is D,L-mixed or levorotatory, with cyclodextrin or cyclodextrin derivatives, to a process for their preparation and the use thereof. In the invention, the butylphthalide is complexed with cyclodextrin or cyclodextrin derivatives, preferably with hydroxypropyl-β-cyclodextrin, in order to increase the water-solubility of butylphthalide, develop clinical solid or liquid formulations and improve the therapeutic effect of butylphthalide. The inclusion complex, in which the molar ratio of butylphthalide to cyclodextrin or cyclodextrin derivatives is in the range of 1:1-10, can be used to prepare infusion, injection, injectable powder, liquids for oral administration, syrup, tablets, granules, dispersible tablets and others.

TECHNICAL FIELD

The present invention relates to pharmaceutical compositions. Moreparticularly, it relates to the inclusion complexes of butylphthalide,which is D,L-mixed or levorotary, with cyclodextrin or its derivatives,to a process for their preparation and the use thereof.

BACKGROUND ART

Butylphthalide is a water insoluble oily compound with the followingformula:

There are two optical isomers, levorotary and dextrorotarybutylphthalide, due to the presence of a chiral carbon therein. Chinesepatent application No. 98125618.X disclosed the use of levorotarybutylphthalide in the preparation of pharmaceutical compositions forpreventing thrombosis and platelet agglomeration. It was found thatbutylphthalide could regulate the function of NOS-NO-cGMP system and themetabolism of arachidonic acid in the neurocytes after ischemia. Chinesepatent application No. 93117148.2 disclosed the use of racemicbutylphthalide mixture in the preparation of pharmaceuticals forpreventing and treating ischemia-induced diseases in mammals or human.

Butylphtualide can be obtained by extraction from natural celery seedoil or by chemical synthesis, as described in Chinese patent applicationNo. 99109673.8 and the prior reference: Junshan Yang, Yalun Su, ChinesePharmaceutical Bulletin, 1984, 31; 671, which realized the availabilityof butylphthalide.

The pharmaceutical formulations are required to release active agentsquickly and exert therapeutic effects rapidly when they are used totreat ischemia-induced diseases or thrombosis. Usually, the formulationsfor treating acute disease are administrated by intravenousinstillation. However, the butylphthalide can only be formulated intosoft capsules for oral administration because of its oilycharacteristics. Therefore, solubility problem of the butylphthalidemust be resolved firstly in order to obtain injectable dosage forms.

For the purpose of investigation of the clinical value ofbutylphthalide, the present applicant has filed a Chinese patentapplication titled “A inclusion complex of butylphthalide withcyclodextrin derivatives, a process for its preparation and the usethereof” on Jun. 18, 2001, in which solubility problem of butylphthalidewas resolved. However, the levorotatory butylphthalide was not mentionedin that application.

DISCLOSURE OF THE INVENTION

The present invention intends to provide inclusion complexes ofbutylphthalide with cyclodextrin or its derivatives, a process for theirpreparation and the use thereof. In order to improve water-solubility ofbutylphthalide, it is complexed with cyclodextrin or its derivatives,wherein the butylphthalide is D,L-mixed or levorotary, and the inclusioncomplexes may be used to prepare various clinically applicable solid andliquid formulations.

The embodiments according to the present invention are as follows:

An inclusion complex of butylphthalide with cyclodextrin or itsderivatives comprises butylphthalide and cyclodextrin or itsderivatives, wherein the molar ratio of butylphthalide to cyclodextrinor its derivatives is in the range of 1:1-10.

The butylphthalide mentioned above comprises D,L-mixed or levorotatorybutylphthalide.

The cyclodextrin mentioned above is selected from the group consistingof α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

The derivatives of cyclodextrin mentioned above are selected from thegroup consisting of hydroxyethyl-β-cyclodextrin,hydroxypropyl-β-cyclodextrin, dihydroxypropyl-β-cyclodextrin,methyl-β-cyclodextrin, glucose cyclodextrin, maltose cyclodextrin,meltotriose cyclodextrin, carboxymethyl cyclodextrin, and sulfonylalkylcyclodextrin.

Among the derivatives of cyclodextrin mentioned above,hydroxypropyl-β-cyclodextrin is preferred.

A process for preparing the inclusion complex of butylphthalide withcyclodextrin or its derivatives is provided as follows:

A solution with a concentration of 5-60% is prepared by addingcyclodextrin or its derivatives into a suitable solvent vehicle. Aliquid inclusion complex of butylphthalide with cyclodextrin or itsderivatives is obtained by adding butylphthalide into the abovesolution, stirring to provide a clear and transparent solution withoutoil drops, wherein the molar ratio of butylphthalide to cyclodextrin orits derivatives is in the range of 1:1 to 1:10.

The process mentioned above may further comprise drying the liquidinclusion complex of butylphthalide with cyclodextrin or its derivativesat the temperature of 40-80° C. to obtain a solid inclusion complex ofbutylphthalide with cyclodextrin or its derivatives.

The process mentioned above may also comprise concentrating the liquidinclusion complex of butylphthalide with cyclodextrin or its derivativesuntil the concentration of cyclodextrin or its derivatives is 10-15%(W/V), cooling the solution for, e.g. about 12 hours to obtain whiteprecipitate, filtering, and drying at 40-80° C., to obtain a solidinclusion complex of butylphthalide with cyclodextrin or itsderivatives.

A process for preparing the inclusion complex of butylphthalide withcyclodextrin or its derivatives according to another aspect of thepresent invention comprises placing cyclodextrin or its derivatives intoa colloid mill or mortar, adding an appropriate amount of suitablesolvent vehicle, and stirring the mixture to provide a paste; addingbutylphthalide into the paste described above, grinding for about 1-5hours to provide a homogenous and viscous paste, then filtering thepaste, and drying at 40-80° C. to obtain a solid inclusion complex ofbutylphthalide with cyclodextrin or its derivatives, wherein the molarratio butylphthalide to cyclodextrin or its derivatives is in the rangeof 1:1-10.

A process for preparing the inclusion complex of butylphthalide withcyclodextrin or its derivatives according to yet another aspect of thepresent invention comprises adding cyclodextrin or its derivatives intoa suitable solvent vehicle to obtain a solution with a concentration of5-60%, dissolving the butylphthalide into an appropriate amount ofethanol with purity of 99%, mixing the two solutions, stirring, anddrying to obtain a solid inclusion complex of butylphthalide withcyclodextrin or its derivatives, wherein the molar ratio butylphthalideto cyclodextrin or its derivatives is in the range of 1:1-10.

The drying method mentioned above may be any drying method, such asdirect drying, spray drying, or freeze-drying.

Examples of the above-mentioned solvent vehicles are water, ethanol,methanol, propanol, isopropanol, ethylene glycol, propylene glycol,glycerin, or acetone, or the mixture of any two or more above-mentionedsolvent vehicles, wherein water is preferred.

Such liquid inclusion complex of butylphthalide with cyclodextrin or itsderivatives may be directly used to produce liquid formulations, such asinfusion, injection, injectable powder, liquids for oral administration,syrup, and the like; The solid inclusion complex of butylphthalide withcyclodextrin or its derivatives may be used to produce solidformulations, such as tablets, capsules, granules, dispersible tablets,and the like.

Not wish to be bound by any theory, the inventors believe thatcyclodextrin or its derivatives could trap the butylphthalide into theirtubular structure to generate an inclusion complex of butylphthalidewith cyclodextrin or its derivatives, thereby improving thewater-solubility of butylphthalide. Accordingly, the active ingredientbutylphthalide in the form of inclusion complexes can be directlyapplied in solid or liquid dosage forms. Limitations such as poorwater-solubility, disability to be directly applied in solid, especiallyinjectable dosage forms can be overcome.

Cyclodextrin or its derivatives are water-soluble pharmaceuticalexcipients with little toxicity. The inclusion complexes ofbutylphthalide with cyclodextrin or its derivatives prepared thereby aresuitable to be formulated into various liquid and solid dosage forms.The inclusion complexes have the advantages such as goodwater-solubility and little vascular irritation. The solubility ofinclusion complex of butylphthalide with hydroxypropyl-o-cyclodextrin inwater at 25° C. is 924 mg/100 ml. The inclusion complex is particularlyapplicable for preparing liquid dosage forms. The present inventionovercomes the limitation that butylphthalide cannot be used to prepareliquid formulations. Due to the fact that the water-solubility isimproved, the resulting solid dosage forms have the advantages such asrapid disintegration, good solubility and high bioavailability, which ismore applicable for clinical use.

The vascular irritation assay using inclusion complex of butylphthalidewith hydroxypropyl-β-cyclodextrin is provided as follows:

Eight rabbits were divided into two groups, namely, test group andcontrol group. For the test group, 2.45 g/kg of the inclusion complextogether with 40 ml of 5% glucose were instilled via the marginal earvein of a rabbit at the rate of 1.5 ml/min. The administration was onceper day and lasted for 3 days. For the control group, 10% acetic acidwas administrated into the ear vein on one side and 5% glucose injectionwas instilled into the rabbit ear on the opposite side serving asnegative control. The administration lasted for 3 days. Results showedthat there was no topical abnormity in the test group after 3 days,similar to the negative control of 5% glucose injection. However,topical hyperaemia, thickening, and exudation were observed after 10%acetic acid injection.

The assay suggests that instillation of the inclusion complex has littlevascular irritation, and that the inclusion complex can be used toproduce injectable dosage forms.

BEST MODE FOR CARRYING OUT THE INVENTION

In the examples according to the present invention,hydroxypropyl-β-cyclodextrin is preferably used as trapping agent.

In the examples according to the present invention, suitable solventvehicle for dissolving cyclodextrin or its derivatives is water.

To illustrate the present invention, the following examples areparticularly described, but the present invention is not intended to belimited thereto.

EXAMPLE 1 Preparation of the Solid Inclusion Complex of Butylphthalidewith hydroxypropyl-β-cyclodextrin

The inclusion complex is prepared by

(1) weighing 32.38 g (0.0210 mol) hydroxypropyl-β-cyclodextrin, addingit into 400 ml distilled water, and dissolving it with stirring;

(2) weighing 1 g (0.0052 mol) butylphthalide separately, and adding itinto the hydroxypropyl-β-cyclodextrin solution mentioned above;

(3) stirring the mixed solution for 20 minutes by magnetic stirringmethod at a speed that the solution cannot be spattered, until thesolution is clear and transparent, to obtain the liquid inclusioncomplex of butylphthalide with hydroxypropyl-β-cyclodextrin;

(4) filtering the liquid inclusion complex of butylphthalide withhydroxypropyl-β-cyclodextrin through a film, dividing it into vials, andfreeze-drying it.

IR (KBr): 3393.46, 2931.26, 1158.24, 1081.60, 1032.07, 946.55,580.68.¹³C-NMR: δ 131.47, 105.07, 84.03, 76.29, 75.04, 74.93, 62.89 ppm.

EXAMPLE 2 Preparation of the Solid Inclusion Complex of LevorotatoryButylphthalide with Hydroxypropyl-β-cyclodextrin

The solid inclusion complex is prepared by

(1) weighing 32.38 g (0.0210 mol) hydroxypropyl-β-cyclodextrin, addingit into a mixed solvent of 400 ml distilled water and 20 ml absoluteethanol, and dissolving it with stirring;

(2) weighing 1 g (0.0052 mol) levorotatory butylphthalide separately,and adding it into the hydroxypropyl-β-cyclodextrin solution mentionedabove;

(3) stirring the mixed solution for 20 minutes by magnetic stirringmethod at a speed that the solution cannot be spattered, until thesolution is clear and transparent, to obtain the liquid inclusioncomplex of levorotatory butylphthalide withhydroxypropyl-β-cyclodextrin;

(4) concentrating the liquid inclusion complex of levorotatorybutylphthalide with hydroxypropyl-β-cyclodextrin, and drying it underreduced pressure, to obtain the solid inclusion complex of levorotatorybutylphthalide with hydroxypropyl-β-cyclodextrin.

EXAMPLE 3 Preparation of the Solid Inclusion Complex of Butylphthalidewith hydroxypropyl-β-cyclodextrin

The solid inclusion complex is prepared by

(1) weighing 8.2 g (0.0053 mol) hydroxypropyl-β-cyclodextrin, placing itinto a mortar, adding about 4 ml water and grinding the mixture into apaste; then weighing 1 g (0.0052 mol) butylphthalide and adding it intothe mortar;

(2) grinding the mixture for 2 hours to obtain a homogenous and viscouspaste, filtering the paste, then drying at 60° C. for 4 hours andgrinding, to obtain the target inclusion complex.

EXAMPLE 4 Preparation of Lyophilized Injectable Powder using theInclusion Complex of Levorotatory Butylphthalide withhydroxypropyl-β-cyclodextrin

The lyophilized injectable powder is prepared by

(1) weighing 1 g (0.0052 mol) levorotatory butylphthalide;

(2) weighing 82 g (0.053 mol) hydroxypropyl-β-cyclodextrin separatelyand dissolving it into 150 ml distilled water;

(3) adding the levorotatory butylphthalide into thehydroxypropyl-β-cyclodextrin solution mentioned above and stirring themixture;

(4) placing the mixture into a freeze drier, freeze-drying and cappingto obtain the lyophilized injectable powder.

EXAMPLE 5 Preparation of Saline Infusion of the Inclusion Complex ofButylphthalide with hydroxypropyl-β-cyclodextrin

The saline infusion of the inclusion complex is prepared by

(1) weighing 32.38 g (0.0210 mol) hydroxypropyl-β-cyclodextrin, addingit into 400 ml distilled water and dissolving with stirring, adding 0.5g active carbon, then stirring and heating to 80° C. for 14 minutes, andfiltering to remove active carbon;

(2) weighing I g (0.0052 mol) butylphthalide separately and dissolvingit into 10 ml ethanol, adding the solution into thehydroxypropyl-β-cyclodextrin solution mentioned above, and magneticallystirring for 20 minutes (the speed is controlled so that the liquidcannot be spattered) to obtain a clear and transparent solution of theinclusion complex of butylphthalide with hydroxypropyl-β-cyclodextrinwithout oil drops of butylphthalide;

(3) supplementing water to reach a volume of 800 ml, adding 7-8 ginjectable sodium chloride, measuring pH and adjusting the pH to 3.5-7with 0.05 N of HCl and 0.05 N of NaOH, supplementing water to reach avolume of 1000 ml, adding 0.1 g active carbon, and stirring for 20minutes;

(4) separating carbon from the solution, filling the solution intobottles (100 ml/bottle), and autoclaving at 115° C. for 30 minutes.

EXAMPLE 6 Preparation of Glucose Infusion of the Inclusion Complex ofButylphthalide with hydroxypropyl-β-cyclodextrin

The glucose infusion of the inclusion complex is prepared by

(1) preparing the solution of the inclusion complex of butylphthalidewith hydroxypropyl-β-cyclodextrin as described in step (1) and (2) ofEXAMPLE 5;

(2) weighing 50 g injectable glucose, adding water to reach a volume of100 ml and dissolving with stirring, then adding 0.1 g active carbon andheating the mixture until the mixture begin to boil and maintaining thatstatus for 15 minutes, then removing carbon;

(3) adding the glucose solution into the solution of inclusion complex,supplementing water to reach a volume of 800 ml, and adjusting its pH to4 with 0.05 N of HCl and 0.05 N of NaOH, supplementing water to reach avolume of 1000 ml, then adding 0.1 g active carbon into the solution,and stirring the solution for 20 minutes;

(4) filtering the solution coarsely and finely with filters or filterstick (pore size of 1.0 μm, 0.45 μm, or 0.22 μm), filling it intobottles and autoclaving at 115° C. for 30 minutes.

EXAMPLE 7 Preparation of Sterile Injectable Powder using the InclusionComplex of Levorotatory Butylphthalide with hydroxypropyl-β-cyclodextrin

The sterile injectable powder is prepared by

(1) weighing 32.38 g (0.0210 mol) hydroxypropyl-β-cyclodextrin in asterile operation room, dissolving it into water to reach a volume of 90ml, adding 0.1 g active carbon into the solution, then heating themixture until the mixture begin to boil and maintaining that status for15 minutes, and filtering to remove the carbon;

(2) weighing 1 g (0.0052 mol) levorotatory butylphthalide and adding itinto the solution of hydroxypropyl-β-cyclodextrin;

(3) magnetically stirring the mixed solution for 20 minutes (the speedis controlled so that the liquid cannot be spattered) to obtain a clearand transparent solution of the inclusion complex of levorotatorybutylphthalide with hydroxypropyl-β-cyclodextrin without oil drop ofbutylphthalide;

(4) supplementing water to reach a volume of 100 ml, filtering through0.22 μm membrane, filling into 10 ml vials (2-3 ml per vial), freezedrying and capping.

EXAMPLE 8 Complexation Levorotatory Butylphthalide with β-cyclodextrin

The complexation process is conducted by

Weighing 3.5 g β-cyclodextrin, adding it into 100 ml distilled water andheating the mixture at 40-60° C. to dissolve β-cyclodextrin, then adding1 g levorotatory butylphthalide and mechanically stirring for 2-3 hours,cooling in the refrigerator for 4 hours, filtering, washing with ethanoland then drying to obtain the inclusion complex of levorotatorybutylphthalide with β-cyclodextrin. The inclusion complex is formulatedinto various solid dosage forms such as tablets and capsules, etc.

1. An inclusion complex of butylphthalide with cyclodextrin orcyclodextrin derivatives, comprising butylphthalide and cyclodextrin orcyclodextrin derivative, wherein the molar ratio of butylphthalide tocyclodextrin or cyclodextrin derivatives is 1:1-10.
 2. The inclusioncomplex according to claim 1, wherein said butylphthalide is D,L-mixedor levorotatory butylphthalide.
 3. The inclusion complex according toclaim 1, wherein said cyclodextrin is selected from the group consistingof α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.
 4. The inclusioncomplex according to claim 1, wherein said cyclodextrin derivatives areselected from the group consisting of hydroxyethyl-β-cyclodextrin,hydroxypropyl-β-cyclodextrin, dihydroxypropyl-β-cyclodextrin,methyl-β-cyclodextrin, glucose cyclodextrin, maltose cyclodextrin,meltotriose cyclodextrin, carboxymethyl cyclodextrin and sulfonylalkylcyclodextrin.
 5. The inclusion complex according to claim 1 or 4,wherein the cyclodextrin derivative is hydroxypropyl-β-cyclodextrin. 6.A process for preparing the inclusion complex of butylphthalide withcyclodextrin or cyclodextrin derivatives, comprising the steps of addingcyclodextrin or cyclodextrin derivatives into a suitable solvent vehicleto obtain a solution with a concentration of 5-60%, addingbutylphthalide into the solution, stirring to obtain a liquid inclusioncomplex of butylphthalide with cyclodextrin or cyclodextrin derivatives.7. The process according to claim 6, further comprising the step ofdrying the liquid inclusion complex of butylphthalide with cyclodextrinor cyclodextrin derivatives to obtain a solid inclusion complex ofbutylphthalide with cyclodextrin or cyclodextrin derivatives.
 8. Theprocess according to claim 6, further comprising the steps ofconcentrating the liquid inclusion complex of butylphthalide withcyclodextrin or cyclodextrin derivatives into a solution with aconcentration of 10-15% (W/V), cooling to obtain white precipitate,filtering, and drying to obtain a solid inclusion complex ofbutylphthalide with cyclodextrin or cyclodextrin derivatives.
 9. Aprocess for preparing the inclusion complex of butylphthalide withcyclodextrin or cyclodextrin derivatives, comprising the steps ofplacing the cyclodextrin or cyclodextrin derivatives into a colloid millor mortar, adding a suitable solvent vehicle to obtain a paste, addingbutylphthalide into the paste, filtering, and drying to obtain a solidinclusion complex of butylphthalide with cyclodextrin or cyclodextrinderivatives.
 10. A process for preparing the inclusion complex ofbutylphthalide with cyclodextrin or cyclodextrin derivatives, comprisingthe steps of adding cyclodextrin or cyclodextrin derivatives into asuitable solvent vehicle to obtain a solution with a concentration of5-60%, dissolving butylphthalide into a selected amount of ethanol withpurity of 99%, mixing the two solutions, stirring, and drying to obtaina solid inclusion complex of butylphthalide with cyclodextrin orcyclodextrin derivatives.
 11. The process according to claim 6, 9 or 10,wherein said suitable solvent vehicle is selected from the groupconsisting of water, ethanol, methanol, propanol, isopropanol, ethyleneglycol, propylene glycol, glycering, acetone, and a mixed solventvehicle of any two or more of the solvent vehicles.
 12. A pharmaceuticalcomposition comprising a therapeutically effective amount of theinclusion complex according to claim 1 and a suitable carrier.
 13. Thepharmaceutical composition according to claim 12 in a liquid dosageform.
 14. The pharmaceutical composition according to claim 12 in asolid dosage form.
 15. A method of treating ischemia-induced diseasecomprising administering a therapeutically effective amount of theinclusion complex according to claim 1 to a patient.
 16. A method oftreating thrombosis comprising administering a therapeutically effectiveamount of the inclusion complex according to claim 1 to a patient.